A Circular Antenna is a very useful VHF antenna. It responds well above 50Mhz. Normally the antenna is constructed out of metal tubing (usually copper or aluminum).

The antenna design is a half-wave dipole bent into a circular shape. The feedpoint is in the middle of the dipole. The two ends of the dipole are not electrically connected. They are separated by an insulator.

                   __   __
                  / _XXX_ \
                 / /     \ \
                / /       \ \
                \ \       / /
                 \ \_____/ /
                  \___F___/

 X is the insulator
 F is the feedpoint
                           wavelength
 The circumference is:   --------------
                               2

The circular antenna is normally used parallel to the surface of the earth. The antenna has an omnidirectional pattern of radiation in all alzimuth directions.